Methods of reducing skin irritation associated with shaving

ABSTRACT

Methods for reducing skin irritation associated with shaving (i.e., before, during, and/or after shaving) using compositions including a lower alcohol and water in a weight ratio of about 20:80 to 100:0, between at least 0.5% and 8.0% by weight thickener system comprised of at least one emulsifier, each emulsifier present in at least 0.05% by weight wherein the composition free of auxiliary thickeners has a viscosity of at least 4,000 centipoise at 23 degrees C.

BACKGROUND OF THE INVENTION

[0001] Removal of unwanted body hair has been a regular part of dailygrooming for centuries. Shaving is by far the most common method of hairremoval for both men and women. It is quick and easy, painless,effective, and inexpensive. The results last only one to three days,however, hence shaving requires a dedicated effort to remain hair-free.Shaving is performed with a razor on wet skin using shaving cream orother lubricants, orienting the razor against the direction of hairgrowth. For sensitive areas, shaving in the direction of hair growth mayreduce cuts. The most common problems associated with shaving are skinirritation, nicks and cuts in the skin, and ingrown hair(pseudofolliculitis barbae). Some skin irritation or trauma isunavoidable because some stratum corneum is removed along with the hairand because the skin is degreased and dried by the surfactants used inshaving products.

[0002] Control of skin irritation related to shaving is of concern tomen and women alike. One of the most effective methods for controllingskin irritation is through the use of an after-shave composition.After-shave compositions are intended to not only to relieve skinirritation but also to provide a cooling and refreshing feeling andimpart a mild astringent effect which tightens the skin. They also mayact in antimicrobial fashion, reducing the presence of bacteria and thusprotecting the skin from infection while it recovers from the mildinjury.

[0003] Numerous types of after-shave compositions are known. They cantake the form of a lotion, gel, quick-breaking foam, or balm andtypically contain significant levels of alcohol, which in addition tobeing antiseptic provides a cooling and astringent effect and enhancesthe drying rate of the composition when applied to skin. The presence ofalcohol also serves to prevent contamination of the composition bymicroorganisms, both during manufacture and storage and after thecomposition's container is opened and put into use.

[0004] Prior art compositions have sought to eliminate the stingingassociated with the use of volatile alcohols by reducing the amount ofalcohol present, which also reduces or eliminates the beneficial effectsof alcohol. Conversely, anhydrous compositions which combine 20% to 50%alcohol with 40% to 70% low viscosity silicone fluids are claimed tohave less stinging and burning although at significantly higher costthan alcohol/water compositions.

[0005] Known methods of reducing irritation and improving skin conditioninclude incorporation of active therapeutic ingredients into after-shavecompositions. Such active ingredients include aloe vera, aluminumchlorohydrate, chamomile combined with niacinamide, non-steroidalanti-inflammatory agents, and panthenol. The use of hydrolyzed soyprotein in combination with cocamidopropyl dimethylamine propionate isalso known.

[0006] Other methods of reducing skin irritation associated with shavingare sought.

SUMMARY OF THE INVENTION

[0007] This invention provides methods of reducing skin irritationassociated with shaving (i.e., before, during, and/or after shaving)facial hair or nonfacial hair. The methods include applying to skinvarious formulations, which typically are preservative-free, have goodapplication aesthetics, provide immediate cooling and skin tightening,evaporate quickly, have a pleasant fragrance, and leave the skin lookingand feeling smooth and soft after both single and multiple applications.Additionally, preferred formulations maintain or improve the skincondition after multiple applications and no slimy or abnormal feelingis noticed during post application washing.

[0008] In one method of reducing skin irritation associated withshaving, the method includes applying to skin a composition thatincludes:

[0009] a) a lower alcohol and water in a weight ratio of about 20:80 to100:0, and

[0010] b) about 0.5% to about 8% by weight of a thickener system, basedon the total weight of the composition, wherein the thickener systemcomprises at least about 0.05% by weight of at least one emulsifier,based on the total weight of the composition, wherein the emulsifiercomprises:

[0011] (i) at least one hydrophobic group selected from the groupconsisting of:

[0012] A. an alkyl group of at least 16 carbon atoms;

[0013] B. an alkenyl group of at least 16 carbon atoms; and

[0014] C. an aralkyl or an aralkenyl group of at least 20 carbon atoms;and

[0015] (ii) at least one hydrophilic group selected from the groupconsisting of:

[0016] A. an ethylene oxide- and/or propylene oxide-containing groupbonded to the hydrophobic group through an ether or ester bond andoptionally terminated with a (C1-C36)alkyl ester, (C2-C36)alkenyl ester,or (C6-C36)alkaryl ester;

[0017] B. an alcohol group;

[0018] C. a polyhydric alcohol group;

[0019] D. an ester or ether group of a polyhydric alcohol orpolyalkoxylated derivative thereof having 2-150 moles of alkylene oxideper mole of hydrophobic group;

[0020] E. an ester or ether group of sorbitan or polyalkoxylatedderivative thereof; and

[0021] F. combinations of these groups;

[0022] wherein the composition has a viscosity of at least about 4,000centipoise at 23° C. when in the absence of an auxiliary thickener, asmeasured using a very low shear viscometer and T spindles with aheliopath adapter.

[0023] In one method of reducing skin irritation associated withshaving, the method includes applying to skin a composition thatincludes:

[0024] a) a lower alcohol and water in a weight ratio of about 20:80 to100:0, and

[0025] b) about 0.5% to about 8% by weight of a thickener system, basedon the total weight of the composition, wherein the thickener systemcomprises at least about 0.05% by weight of at least one emulsifier,based on the total weight of the composition, wherein the emulsifiercomprises:

[0026] (i) at least one hydrophobic group selected from the groupconsisting of:

[0027] A. an alkyl group of at least 24 carbon atoms;

[0028] B. an alkenyl group of at least 24 carbon atoms; and

[0029] C. an aralkyl or an aralkenyl group of at least 24 carbon atoms;and

[0030] (ii) at least one hydrophilic group selected from the groupconsisting of:

[0031] A. an ethylene oxide- and/or propylene oxide-containing groupbonded to the hydrophobic group through an ether or ester bond andoptionally terminated with a (C1-C36)alkyl ester, (C2-C36)alkenyl ester,or (C6-C36)alkaryl ester;

[0032] B. an alcohol group;

[0033] C. a polyhydric alcohol group;

[0034] D. an ester or ether group of a polyhydric alcohol orpolyalkoxylated derivative thereof having 2-150 moles of alkylene oxideper mole of hydrophobic group;

[0035] E. an ester or ether group of sorbitan or polyalkoxylatedderivative thereof; and

[0036] F. combinations of these groups;

[0037] wherein the composition has a melt temperature of greater thanabout 25° C. and a viscosity of at least about 4,000 centipoise at 23°C. when in the absence of an auxiliary thickener, as measured using avery low shear viscometer and T spindles with a heliopath adapter.

[0038] In one method of reducing skin irritation associated withshaving, the method includes applying to skin a composition thatincludes:

[0039] a) a major amount of a solvent comprising a lower alcohol andwater in a weight ratio of about 60:40 to 95:5, and

[0040] b) about 0.5% to about 8% by weight of a thickener system, basedon the total weight of the composition, wherein the thickener systemcomprises at least about 0.05% by weight of one or more emulsifiers,based on the total weight of the composition, wherein at least one ofthe emulsifiers is solid at room temperature;

[0041] wherein the composition has a melt temperature of greater thanabout 25° C. and a viscosity of at least about 45,000 centipoise after19 days at 23° C. when in the absence of an auxiliary thickener, asmeasured using a very low shear viscometer and T spindles with aheliopath adapter.

[0042] In one method of reducing skin irritation associated withshaving, the method includes applying to skin a composition thatincludes:

[0043] a) a lower alcohol and water in a weight ratio of about 20:80 to100:0, and

[0044] b) about 0.5% to about 8% by weight of a thickener system, basedon the total weight of the composition, wherein the thickener systemcomprises at least about 0.05% by weight of at least two emulsifiers,based on the total weight of the composition, wherein at least oneemulsifier comprises:

[0045] (i) at least one hydrophobic group selected from the groupconsisting of:

[0046] A. an alkyl group of at least 16 carbon atoms;

[0047] B. an alkenyl group of at least 16 carbon atoms; and

[0048] C. an aralkyl or an aralkenyl group of at least 20 carbon atoms;and

[0049] (ii) at least one hydrophilic group selected from the groupconsisting of:

[0050] A. an ethylene oxide- and/or propylene oxide-containing groupbonded to the hydrophobic group through an ether or ester bond andoptionally terminated with a (C1-C36)alkyl ester, (C2-C36)alkenyl ester,or (C6-C36)alkaryl ester;

[0051] B. an alcohol group;

[0052] C. a polyhydric alcohol group;

[0053] D. an ester or ether group of a polyhydric alcohol orpolyalkoxylated derivative thereof having 2-150 moles of alkylene oxideper mole of hydrophobic group;

[0054] E. an ester or ether group of sorbitan or polyalkoxylatedderivative thereof; and

[0055] F. combinations of these groups;

[0056] and wherein at least one emulsifier comprises:

[0057] (i) at least one hydrophobic group selected from the groupconsisting of:

[0058] A. an alkyl group of at least 16 carbon atoms;

[0059] B. an alkenyl group of at least 16 carbon atoms; and

[0060] C. an aralkyl or an aralkenyl group of at least 20 carbon atoms;and

[0061] (ii) at least one hydrophilic group selected from the groupconsisting of:

[0062] A. an amide group;

[0063] B. a short chain ester of a long chain alcohol or acid;

[0064] C. a polyglucoside group having 1-10 glucose units;

[0065] D. a polyglycerol ester group having 1-15 glycerol units;

[0066] E. a secondary amine group;

[0067] F. a tertiary amine group;

[0068] G. a anionic group;

[0069] H. a zwitterionic group; and

[0070] I. combinations of these groups.

[0071] In one method of reducing skin irritation associated withshaving, the method includes applying to skin a composition thatincludes:

[0072] a) a lower alcohol and water in a weight ratio of about 20:80 to95:5; and

[0073] b) about 0.5% to about 8% by weight of a thickener system, basedon the total weight of the composition, wherein the thickener systemcomprises at least about 0.05% by weight of at least one emulsifier,based on the total weight of the composition, wherein the emulsifiercomprises:

[0074] (i) at least one hydrophobic group selected from the groupconsisting of:

[0075] A. an alkyl group of at least 16 carbon atoms;

[0076] B. an alkenyl group of at least 16 carbon atoms; and

[0077] C. an aralkyl or an aralkenyl group of at least 20 carbon atoms;and

[0078] (ii) at least one hydrophilic group selected from the groupconsisting of:

[0079] A. an amide group;

[0080] B. a short chain ester of a long chain alcohol or acid;

[0081] C. a polyglucoside group having 1-10 glucose units;

[0082] D. a polyglycerol ester group having 1-15 glycerol units;

[0083] E. a secondary amine group;

[0084] F. a tertiary amine group;

[0085] G. a anionic group;

[0086] H. a zwitterionic group; and

[0087] I. combinations of these groups;

[0088] wherein the composition has a viscosity of at least about 4,000centipoise at 23° C. when in the absence of an auxiliary thickener, asmeasured using a very low shear viscometer and T spindles with aheliopath adapter.

DEFINITIONS

[0089] “After-shave” as used herein refers to a lotion, gel, cream,foam, stick, balm, or mousse that is applied to skin. The term is alsounderstood to include compositions applied prior to, during, or aftershaving which may facilitate the shaving process by improving the shave,reducing irritation, adding lubricity, disinfecting, reducing discomfortof any kind, and any combination thereof.

[0090] “Ambient temperature” as used herein refers to the temperaturerange between about 21° C. and 25° C. (i.e., of about 21° C. to about25° C.).

[0091] “Auxiliary thickeners” as used herein refers to additives (otherthan the emulsifiers which comprise the thickener system describedbelow), which increase the viscosity of the solvent phase even in theabsence of the thickener system. Certain auxiliary thickeners may actsynergistically with the thickener system to increase the viscosity ofthe resultant formula. Auxiliary thickeners include but are not limitedto soluble and swellable polymers (e.g. polyacrylic acid polymers suchas CARBOPOL, BF Goodrich, Cleveland, Ohio) and associative colloidalthickeners such as silica, magnesium aluminum silicate, and the like.

[0092] “Emollient” as used herein refers broadly to materials which arecapable of maintaining or improving the moisture level, compliance, orappearance of the skin when used repeatedly.

[0093] “Emulsifier” as used herein is synonymous with “surfactant” andrefers to molecules comprising hydrophilic (polar) and hydrophobic(non-polar) regions on the same molecule.

[0094] “Emulsion” as used herein refers to a stable dispersion of oneliquid in a second immiscible liquid.

[0095] “Lotion” means liquid or cream, free of any propellant.

[0096] “Melt temperature” (Tm) as used herein refers to the temperatureat which compositions or emulsions of the present invention dramaticallylose viscosity.

[0097] “Polymer” as used herein refers to a natural or syntheticmolecule having repetitive units and a number average molecular weightof at least 20,000.

[0098] “Solvent,” “solvent system” or “hydroalcoholic solvent” as usedherein refer to the alcohol and water combination in the presentinvention.

[0099] “Stable” as used herein refers to a composition that displaysless than or equal to 10% by volume separation after centrifuging at2275×g for 30 minutes at ambient temperature.

[0100] “Surfactant” as used herein is synonymous with “emulsifier,” thedefinition of which is given above.

[0101] “Thickener system” as used herein refers to a combination of atleast one emulsifier, and preferably at least two emulsifiers, eachpresent in a concentration of at least 0.05% by weight capable ofproviding a viscosity of at least 4,000 centipoise at 23° C. to thecompositions used in the methods of the present invention withoutauxiliary thickeners.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0102] The invention provides methods of reducing skin irritationassociated with shaving using a composition that includes a lower chainalcohol, water, and thickening system. Alcohols used in thesecompositions are first discussed followed by a discussion of thickeningsystems. Ingredients that are optionally added to the composition, suchas emollients, are then discussed, followed by a discussion of how toprepare compositions used in the methods of the present invention.

[0103] Alcohol

[0104] The alcohol used in the compositions is a lower hydrocarbon chainalcohol such as a C1-C4 alcohol. In preferred embodiments the alcohol ischosen from ethanol, 2-propanol, or n-propanol, and most preferablyethanol. Ethanol is a preferred alcohol for certain embodiments since ithas an odor acceptable to consumers. The invention anticipates that asingle alcohol may be used or that a blend of two or more alcohols mayform the alcohol content of the composition.

[0105] The alcohol to water ratio in the compositions used in themethods of the present invention is between about 20:80 and 100:0 byweight (i.e., within a range of about 20:80 to about 100:0).Compositions having alcohol to water ratios below about 20:80 fail toprovide much benefit in terms of rapid evaporation or cooling. Preferredcompositions have alcohol to water ratios within the range of about35:65 (and more preferably 40:60) to about 95:5 by weight range. In aneven more preferred embodiment the alcohol:water ratio is between about50:50 and 85:15, more preferably between about 60:40 and about 75:25,and most preferably the alcohol:water ratio is between about 64:36 and72:28 by weight. Higher alcohol to water ratios are used in a preferredembodiment for optimum antimicrobial activity and to ensure thecomposition is fast drying.

[0106] Thickener System

[0107] The thickener system useful in the compositions used in themethods of the invention affects the cosmetic attributes of the finalcomposition. Preferably, compositions of the invention should maintainan acceptable viscosity at 25° C. and preferably up to 35° C. Also, themost preferred formulations are stable to heat and cool cycles (heatingup to 50° C. or higher and cooling to ambient temperature) as well asfreeze/thaw cycles (cooling to −30° C. and warming to ambienttemperature). These attributes are affected by the types and amounts ofemulsifiers chosen which form the thickener system of the presentinvention and are discussed below.

[0108] The thickener system is compatible with the hydroalcoholicsolvent system described above in order to provide acceptable cosmeticproperties and appropriate viscosity. Compositions of this inventionhave a viscosity of at least about 4,000 Centipoise (cps) at 23° C.,preferably at least about 10,000 cps, more preferably at least about20,000, even more preferably at least about 50,000 cps, even morepreferably at least about 90,000 cps, and most preferably at least about100,000 cps, and preferably up to about 500,000 cps, measured using avery low shear viscometer such as Brookfield LVDV-I⁺ viscometer and Tspindles with a heliopath adapter. Since the emollient system and otheroptional ingredients may affect the viscosity (either positively ornegatively), the measured viscosity is that of the final compositionwithout any added auxiliary thickeners.

[0109] The viscosity of the compositions used in the methods of thepresent invention is imparted by a thickener system that includes atleast one emulsifier, preferably at least two emulsifiers, and morepreferably at least two emulsifiers from different classes. In apreferred embodiment at least one of the emulsifiers is a solid at roomtemperature. Such emulsifier preferably includes at least one long chainhydrocarbon of at least 16 carbon atoms, preferably at least 18 carbonatoms, and more preferably at least 22 carbon atoms. At loweralcohol:water ratios of greater than about 60:40, the long chainhydrocarbon preferably has greater than 22 carbon atoms. The thickenersystem can be described in terms of the number average chain length, andpreferably has a hydrophobe number average chain length of greater thanabout 22 carbon atoms.

[0110] Emulsifiers used in the compositions of this invention arecomprised of molecules having hydrophilic (polar) and hydrophobic(non-polar) regions on the same molecule and conform to the generalstructure:

(R)_(a)(L)_(b)

[0111] wherein “R” represents a hydrophobic group, “L” represents ahydrophilic group, and “a” and “b” are independently 1 to 4.

[0112] In this invention “R” comprises an alkyl group of at least about16 carbon atoms, preferably at least about 18 carbon atoms, morepreferably at least about 20 carbon atoms, and most preferably at leastabout 22 carbon atoms; alkenyl group of at least about 16 carbon atoms,preferably at least about 18 carbon atoms, and most preferably at leastabout 20 carbon atoms; or aralkyl or aralkenyl group of at least about20 carbon atoms, preferably at least about 24 carbon atoms, and mostpreferably at least about 26 carbon atoms. In a preferred embodiment thealkyl or alkenyl portion of “R” is unbranched.

[0113] In the above formula, “L” represents a hydrophilic group. Forexample, “L” can include an amide group having the structure —NHC(O)R′″or —C(O)NHR′″ where R′″ is hydrogen or an alkyl group of 1-10 carbonatoms optionally substituted in available positions by N, O, and Satoms; an ester group of short chain alcohols or acids (e.g., L=—C(O)OR′or —OC(O)R′ where R′ is C1-C4 branched or straight chain alkyloptionally substituted in available positions by hydroxyl groups); apolyglucoside group having 1-10 glucose units and more preferably 1-3glucose units; a polyglycerol ester group having 1-15 glycerol units,preferably 2-12 glycerol units, and more preferably 3-10 glycerol units;a secondary amine group; a tertiary amine group; and a quaternary aminegroup.

[0114] “L” can also include an anionic group such as a sulfate,sulfonate, phosphate, phosphonate, or carboxylate group, or azwitterionic group having the formula:

—N⁺(R″)₂(CHQ)_(x)L′

[0115] or

[0116] wherein each R″ is independently hydrogen or an alkyl group(having 1-5 carbon atoms) or alkenyl group (having 2-4 carbon atoms),which alkyl or alkenyl groups are optionally substituted with nitrogen,oxygen, or sulfur atoms, including alkyl or alkenyl carboxyl groups; Qis hydrogen or hydroxyl; x is 1 to 4; and L′ is —CO₂ ⁻,—OP(O)(O⁻)(O⁻M⁺), —(O)P(OR′″)(O)(O⁻) (where R′″ is hydrogen or an alkylgroup of 1-10 carbon atoms optionally substituted in available positionsby N, O, or S atoms), —SO₂O⁻, or —OSO₂O⁻, where M⁺ is a positivelycharged counterion present in a molar ratio necessary to achieve a netneutral charge on the emulsifier and is selected from the group ofhydrogen, sodium, potassium, lithium, ammonium, calcium, magnesium, orN⁺R″₄.

[0117] “L” can also include an alcohol group; a polyhydric alcohol groupsuch as, but not limited to, ethylene glycol, butylenes glycol,pentaerythrytol, glycerol, and sorbitol; an ethylene oxide and/orpropylene oxide group, preferably having 2-150 moles of ethylene oxideplus propylene oxide per mole of hydrophobe (“R”), which is bonded tothe hydrophobe through an ether or ester linkage, and optionallyterminated by C1-C36 alkyl, C2-C36 alkenyl ester, or C6-C36 alkarylester (i.e., aralkyl ester); an ester or ether group of a polyhydricalcohol and their polyalkoxylated derivatives; an ester or ether ofsorbitan or polyalkoxylated (i.e., polyalkyleneoxide) sorbitan group,preferably having 2-150 moles of alkylene oxide units per mole ofhydrophobe; as well as combinations of these groups, e.g., apolyethoxylated polyglucoside group. Thus, it will be understood by oneof skill in the art that the emulsifiers can include combinations of all“L” hydrophilic groups described herein (e.g., ester groups and amidegroups in one molecule).

[0118] The hydrophobic and hydrophilic groups on non-ionic emulsifiersare generally selected to have a hydrophile/lipophile balance (HLB) of 2to 20 and more preferably 4 to 16. Furthermore, the weight average HLBof the thickener system is preferably 4 to 16 and more preferably 8 to12. For example, a thickener system comprised of 40% by weight of anemulsifier with an HLB of 10 and 60% by weight of an emulsifier with anHLB of 15 has a weight average HLB of 13.

[0119] The emulsifiers of the thickener systems may be chosen from asingle class of surfactants (e.g., a mixture of chain length alkylpolyglucosides) but is preferably a mixture of emulsifier classes. Manycommercially available emulsifiers are actually comprised of a mixtureof chain lengths. For example, some behenyl alcohol as commerciallysupplied is actually a mixture of alcohols consisting of primarily C22and C20 fractions but contain detectable levels of C24, C18 and C16fractions. For this reason, the chain lengths specified herein refer tothe number average chain length. Furthermore, in multiple emulsifierthickener systems, each emulsifier must be present in a concentration ofat least about 0.05% and more preferably at least about 0.1% by weightto be considered a component of a thickener system. Thickener systems ofthe present invention are capable of achieving high viscosities atrelatively low total emulsifier concentrations. The total concentrationof emulsifiers present as a thickener system for creams and lotions isgenerally less than about 8% by weight, preferably less than about 5% byweight, more preferably less than about 4% by weight, and mostpreferably less than about 3% by weight of the total composition.Typically, the thickener system is present in the composition in anamount of at least about 0.5% by weight, based on the total weight ofthe composition. In the most preferred lotion compositions of thisinvention, the thickener system comprises between about 0.75% by weightto about 5% by weight, more preferably between about 1.0% by weight toabout 3.5% by weight and most preferably between about 1.5% by weight toabout 3% by weight of the composition. As used herein an emulsifier isconsidered part of the thickener system if its presence in the formularesults in an increase in the viscosity of the composition. If a certainemulsifier does not result in increasing the viscosity of thecomposition, it is considered an emollient or stabilizer as definedbelow.

[0120] Preferred methods of the present invention include compositionsthat are substantially free of polymeric thickening agents and have a“melt temperature” (Tm). If compositions are heated above this melttemperature, they dramatically lose viscosity. The compositionspreferably have melt temperatures greater than 25° C. in order tomaintain a high viscosity at room temperature. More preferably the melttemperature is greater than 35° C. in order to maintain viscosity onceapplied to the skin. The most preferred formulations have a melttemperature greater than 40° C. in order to allow shipping and handlingwithout refrigeration. Thickener systems affect the melt temperature ofa given composition. In order to obtain a preferred melt temperature apreferred thickener system includes at least one emulsifier, which issolid at ambient temperature. Preferably, all emulsifiers of a thickenersystem are solid at ambient temperature to increase the melt temperatureof the resultant composition.

[0121] The structure of emulsifiers in a thickener system affects themelt temperature of the resultant composition. In a preferred embodimentat least one emulsifier in a thickener system is capable of promoting acrystalline structure. Crystallinity is promoted by long straight chainalkyl groups, therefore, at least one emulsifier preferably comprises asaturated straight chain hydrocarbon of at least 16, preferably at least18 and most preferably at least 20 carbon atoms. Certain hydrophilichead groups have been found to particularly promote association andcrystallization. Suitable crystalline emulsifiers include alkylalcohols, alkyl polyglucosides, polyglycerol alkyl esters, C1-C4 estersof alkyl alcohols, C1-C4 esters of alkyl carboxylates, optionallysubstituted alkyl amides, alkyl betaines and alkyl phosphates orphospholipids, alkyl quaternary amines, alkyl amine oxidespolyethoxylated alkyl alcohols and alkyl esters of polyethylene glycol.

[0122] In addition to affecting the melt temperature of a composition,the emulsifier chain length also helps to determine the maximum level ofethanol which can be used in the composition and the concentration ofemulsifiers required in the thickener system. At higher levels ofalcohol, longer chain emulsifiers are required to produce viscous stableemulsions. It is believed that higher levels of alcohol tend to swell orsolubilize the emulsifiers to a greater degree than lower levels ofalcohol. Therefore, as the concentration of ethanol increases the chainlength of the hydrocarbon chains in a thickening system must alsoincrease in order to maintain a melt temperature over 35° C. That is,the amount of lower alcohol in the hydroalcoholic system can affect thechoice of surfactant (i.e., emulsifier), and vice versa. For example, ifthe composition includes a lower alcohol to water ratio in excess ofabout 50:50, the thickener system should include at least one surfactanthaving a number average chain length of at least 16 carbon atoms. If thecomposition includes an alcohol to water ratio in excess of about 60:40,the thickener system should include at least one surfactant having anumber average chain length of at least 18 carbon atoms. If thecomposition includes a lower alcohol to water ratio in excess of about64:36, the thickener system should include at least one surfactanthaving a number average chain length of at least 20 carbon atoms.

[0123] For example, systems based on a C16/C18 alkyl polyglucoside(MONTANOV 68 available from Seppic, Inc. of Fairfield, N.J.) incombination with a C18 polyethoxylate (BRIJ 76 available from ICI ofWilmington, Del.) in 68:32 ethanol:water have a melt temperature ofapproximately 35° C. Similar systems having C22 hydrocarbon chains havemelt temperatures of 45° C. or higher. In addition, as the chain lengthof the hydrophobic component in the thickener system increases, theamount of emulsifier required to achieve a certain viscosity decreases.For example, the MONTANOV 68 (C16/C18 alkyl polyglucoside)/BRIJ 76(polyethoxylated C18 alcohol) thickener system requires approximately 5%total emulsifier to achieve a suitable viscosity. A similar system basedon C22 hydrophobes achieves a suitable viscosity at only 2% totalemulsifier.

[0124] The nature and size of hydrophilic head groups of emulsifiers areimportant and help to determine which thickening systems produce viscousstable systems. Certain combinations of emulsifiers will produce viscousstable emulsions. Without being bound by theory, it is believed that thesize, charge, and degree of hydrogen bonding are important parameters todetermine how emulsifiers interact.

[0125] Many preferred thickener systems are capable of producingviscoelastic compositions, which are very stable. By varying the ratioof emulsifiers, the degree of elasticity can be adjusted from almost apurely viscous composition to a highly elastic and even stringycomposition. If emollients are added, increasing the elasticity of thesystem imparts added stability to prevent separation of immiscibleemollients. Excessive elasticity, however, is not preferred since anelastic composition usually does not provide a cosmetically appealingproduct. Addition of certain emulsifiers with at least two hydrophobiccomponents has been shown to limit the viscoelasticity while ensuringviscous stable compositions. A favored class of multiple hydrophobiccomponent emulsifiers are quaternary ammonium salts conformingsubstantially to the following structure:

[0126] where: R′ and R″ are long chain alkyl or alkenyl hydrocarbonchains of at least 16 carbon atoms;

[0127] R′″ is a short chain alkyl group of 1 to 4 carbon atoms,preferably methyl or ethyl;

[0128] R″″ is equivalent to either R′ or R′″ and is preferablyequivalent to R′″; and

[0129] X is a halogen, R′″SO₃—, R′″SO₄—, or R′″CO₂—

[0130] Some preferred structures include distearyldimethylammoniumchloride, dibehenyldimethylammonium chloride, anddibehenyldimethylammonium methosulfate, while dibehenyldimethylammoniummethosulfate is a more preferred structure. Other suitable multiplehydrophobic emulsifiers include dialkylglycerol esters, trialkylglycerolesters, polyglycerol alkyl esters, ethylene glycol dialkylesters,polyethylene glycol dialkylesters, dialkylamides of diamines such asethylene diamine, polyalkylesters of pentaerythritol and dialkyl(optionally ethoxylated) phosphates, and alkyl esters of polyethoxylatedalkyl alcohols.

[0131] The following emulsifier classes are offered as nonlimitingexamples of suitable emulsifiers for use in the present invention.Examples of some preferred emulsifiers are provided for each emulsifierclass.

[0132] Class 1. Alkyl or Alkenyl Polyglucosides:

[0133] where R is a straight chain alkyl or alkenyl group of at least 16carbon atoms, preferably at least 18 carbon atoms, and most preferablyat least 20 carbon atoms; or an aralkyl or aralkenyl group of at least22 carbon atoms, preferably at least 24 carbon atoms and most preferablyat least 26 carbon atoms; and n=0-10 (when n=0, the valence of theoxygen atom is completed by H), preferably 1-5 and more preferably 1-3.

[0134] Nonlimiting examples of preferred alkyl or alkenyl polyglucosideemulsifiers include cetearyl glucoside sold as MONTANOV 68 by Seppic,Inc. of Fairfield, N.J.; behenyl glucoside, produced experimentally asESSAI 624 MP, an alkyl polyglucoside prepared with 92% C-22 alcohol andcorn-derived glucoside by Seppic, Inc.; and oleyl glucoside.

[0135] Class 2. Short Chain Esters of Long Chain Alcohols or Acids:

RC(O)OR′ or ROC(O)R′

[0136] where R is as defined immediately above for Emulsifier Class 1;and R′ is C1-C4 branched or straight chain alkyl group, optionallysubstituted in available positions by hydroxyl groups.

[0137] Some preferred short chain esters of long chain alcohols or acidsinclude but are not limited to methyl behenate sold as KEMESTER 9022 byCrompton Corp., Greenwich, Conn.; methyl stearate sold as KEMESTER 4516by Crompton Corp.; methyl oleate sold as KEMESTER 205 by Crompton Corp.;arachidyl proprionate available as WAXENOL 801 from Alzo of Sayreville,N.J.; behenyl lactate, stearyl acetate; and glycerol monoerucateavailable from Croda, Inc. of Parsippany, N.J.

[0138] Class 3. Alkyl and Alkenyl Alcohols:

R₆—OH

[0139] where R₆ is a straight or branched chain alkyl or alkenylhydrocarbon chain of at least 16 carbon atoms, preferably at least 18,more preferably at least 20 carbon atoms, and most preferably at least22 carbon atoms, optionally substituted in available positions by N, O,or S atoms; or an aralkyl or aralkenyl group of at least 16 carbonatoms, preferably at least 22 carbon atoms, more preferably at least 24carbon atoms, and most preferably at least 26 carbon atoms, optionallysubstituted in available positions by N, O, and S atoms.

[0140] Nonlimiting examples of preferred alkyl and alkenyl alcoholemulsifiers useful in a thickener system of the invention includestearyl alcohol available as LANETTE 18 from Henkel's Emery Division ofCincinnati, Ohio; behenyl alcohol available as LANETTE 22 from Henkel;oleyl alcohol available as NOVOL from Croda; C-24 alcohol available asUNILIN 350 from Petrolite of Tulsa, Okla.; C31 alcohol available asUNILIN 425 from Petrolite; and arachidyl alcohol available as AR-20 fromM. Michel and Co. of New York, N.Y.

[0141] Class 4. Polyglycerol Ester

[0142] where each R₁ is independently hydrogen or a straight chain alkylgroup of at least 16 carbon atoms, preferably at least 18 and morepreferably at least 20 carbon atoms; or an aralkyl or aralkenyl group ofat least 22 carbon atoms, preferably at least 24 carbon atoms, and mostpreferably at least 26 carbon atoms; and n=0 to 15, preferably 1 to 12,and most preferably 2 to 10.

[0143] Some examples of preferred polyglycerol ester emulsifiers usefulin a thickener system of the present invention include but are notlimited to decaglycerol monostearate available as POLYALDO 10-1-S fromLonza Inc. of Fairlawn, N.J.; tetraglycerol monostearate available asTETRAGLYN 1-S from Barnet Products Corporation of Englewood Cliffs,N.J.; and decaglyceroltetrabehenate.

[0144] Class 5. Quaternary Amine

[0145] where R is as defined above in Emulsifier Class 1; R₂ is the sameas R₃ or a long chain alkyl or alkenyl hydrocarbon chain of at least 16carbon atoms, preferably at least 18 and more preferably at least 20carbon atoms optionally substituted in available positions by N, O, andS; or an aralkyl or aralkenyl group of at least 22 carbon atoms,preferably at least 24 carbon atoms, and most preferably at least 26carbon atoms; R₃ is a short chain alkyl group of 1 to 4 carbon atoms,preferably methyl or ethyl; R₄ is equivalent to either R₂ or R₃ and ispreferably equivalent to R₃; and X is a halogen, R₅SO₃—, R₅SO₄ ⁻, R₅CO₂⁻, (R₅)₂PO₄ ⁻, or (R₅)PO₄═; where R₅ is defined in Class 6 below.

[0146] Nonlimiting examples of quaternary amine emulsifiers includedibehenyldimethylammonium methosulfate available as INCORQUAT DBM-90from Croda; behenyltrimethylammonium chloride available as NIKKOLCA-2580 from Barnet; and tallowtrimethylammonium chloride available asARQUAD T-27W from Akzo Chemicals, Inc. of Chicago, Ill.

[0147] Class 6. Tertiary Amine and its Protonated Salts

[0148] where R, R₂, and R₃ are as defined above in Class 5 and R₂ and R₃may also be selected from polyethoxylated or polyproxylated alkyl oralkenyl alcohol chains having 1-50 moles of ethylene oxide or propyleneoxide groups per mole of a emulsifier and Y is a halogen, R₅SO₃—,R₅SO₄—, R₅CO₂—, (R₅)PO₄ ⁻, or (R₅)PO₄═, where R₅ is an alkyl or alkenylgroup of 1-22 carbon atoms optionally substituted in available positionsby N, O, and S.

[0149] Some examples of emulsifiers from the class of tertiary aminesand their protonated salts useful in a thickener system of the inventioninclude but are not limited to behenamidopropyldimethylamine availableas INCROMINE BB from Croda; behenamidopropyldimethylamine gluconate;tallowdimethylamine hydrochloride; dihydrogenated tallow methyl amine;stearyl diethanolamine hydrochloride; polyethoxylated stearyldiethanolamine hydrochloride.

[0150] Class 7. Amine Oxides

[0151] where R₂ and R₃ are as defined above for Class 5 and R₆ is asdefined above for Class 3.

[0152] Nonlimiting examples of emulsifiers from the class of amineoxides suitable in a thickener system of the invention includebehenamine oxide (behenyldimethylamine oxide) available as INCROMINEB-30P from Croda; stearamine oxide available as INCROMINE Oxide S fromCroda; behenamidopropyldimethyl amine oxide; andbis(2-hydroxyethyl)tallow amine oxide available as AROMOX T/12 fromAkzo.

[0153] Class 8. Polyethoxylated and/or Polypropoxylated Alcohols andEsters and Derivatives Thereof

[0154] where R₆ is as defined above for Emulsifier Class 3; m=0-200,preferably 2-50, most preferably 4-20;

[0155] p=0 or 1;

[0156] R₈=H or —C(O)—R₁₂,

[0157] where R₁₂ is an alkyl or alkenyl group of 1-36 carbon atomsoptionally substituted by N, O or S, or an aralkyl group of 6 to 36carbon atoms; and

[0158] r=0-50.

[0159] Some examples of preferred emulsifiers from the class ofpolyethoxylated alcohols and esters include but are not limited tosteareth-2 available as BRIJ 72 from ICI Americas Inc. of Wilmington,Del.; steareth-10 available as BRIJ 76 from ICI; beheneth-5 available asNIKKOL BB-5 from Barnet Products Inc.; beheneth-10 available as NIKKOLBB-10 from Barnet; C31 alkyl-10EO available as UNITHOX 450 fromPetrolite Corp. of Tulsa, Okla.; C31 alkyl-40 EO available as UNITHOX480 from Petrolite, and the lauric ester of UNITHOX 480 available fromPetrolite as X-5171.

[0160] Class 9. Zwitterionics

RN⁺(R₇)₂(CHQ)_(x)L′ or

[0161] wherein R is as defined above for Emulsifier Class 1; each R₇ isindependently hydrogen or an alkyl group (having 1-5 carbon atoms) oralkenyl group (having 2-4 carbon atoms), which alkyl or alkenyl groupsare optionally substituted with nitrogen, oxygen, or sulfur atoms,including alkyl or alkenyl carboxyl groups; Q is hydrogen or hydroxyl; xis 1 to 4; and L′ is —CO₂ ⁻, —OP(O)(O⁻)(O⁻M⁺), —(O)P(OR′″)(O)(O⁻) (whereR′″ is hydrogen or an alkyl group of 1-10 carbon atoms optionallysubstituted in available positions by N, O, or S atoms) —SO₂O⁻, or—OSO₂O⁻, where M⁺ is a positively charged counterion present in a molarratio necessary to achieve a net neutral charge on the emulsifier and isselected from the group of hydrogen, sodium, potassium, lithium,ammonium, calcium, magnesium, or N⁺R′₄ where each R′ is independently analkyl group of 1 to 4 carbon atoms optionally substituted with N, O, orS atoms.

[0162] Nonlimiting examples of emulsifiers from the class of zwitterionsuseful in the emulsifier system of the invention includestearamidopropylPG-dimmonium chloride phosphate available asPHOSPHOLIPID SV from Uniqema of Paterson, N.J.; and behenyl betaineavailable as INCRONAM B-40 from Croda.

[0163] Class 10. Alkyl and Alkenyl Amides

[0164] where R₆, R₇, and R₁₂ are as defined above in Classes 3, 9, and 8respectively.

[0165] Examples of some preferred emulsifiers from the class of alkyland alkenyl amides useful in a thickener system of the invention includebut are not limited to behenamide available as KEMAMIDE B from CromptonCorp.; stearamide available as UNIWAX 1750 from Petrolite;Behenamidopropyldimethyl amine available as INCROMINE BB from Croda;stearyldiethanolamide available as LIPAMIDE S from Lipo Chemicals Inc.of Paterson, N.J.; and Erucamide available as ARMID E from Akzo.

[0166] Class 11. Esters and Ethers of Polyhydric Alcohols

[0167] wherein t=0-4; each R₉ is independently chosen from H, —CH₂OR₁₀,—OH, or a hydrocarbon chain of 1 to 4 carbon atoms, preferablycontaining 1 carbon atom; s=0 or 1; wherein R₁₀=H, R₈, or R₁₂ wherein R₈and R₁₂ are defined above for Emulsifier Class 8.

[0168] Examples of esters and ethers include glycerol monobehenate,pentaerythritol distearate and glycerol tribehenate.

[0169] Esters and ethers of polyethoxylated polyhydric alcohols are alsouseful. For example, these include but are not limited topolyethoxylated glycerol monostearate, polyethoxylated penta erythritolbehenate, polyethoxylated propylene glycol monostearate.

[0170] Class 12. Anionics [(R₁₄)_(a)L_(d)^(−c)](M^(+b))e

[0171] where R₁₄ is an alkyl, alkenyl, or aralky group of at least 16carbon atoms, preferably at least 18 carbon atoms and most preferably atleast 20 carbon atoms optionally comprising oxygen, nitrogen, or sulfuratoms within or substituted upon the alkyl or alkenyl chain; or apolyethoxylated and/or polypropoxylated alkyl, alkenyl or aralkyl group,which alkyl, alkenyl, or aralkyl group comprises at least 16 carbonatoms, preferably at least 18 carbon atoms and most preferably at least20 carbon atoms optionally comprising oxygen, nitrogen, or sulfur atomswithin or substituted upon the alkyl, alkenyl, or aralkyl chain. WhenR₁₄ comprises a polyethoxylated or polypropoxylated substituent or acopolymeric substituent of ethylene oxide and propylene oxide, thesesubunits are present in amounts of 1 to 100 moles, preferably 1 to 20moles per mole of hydrophobe; L is sulfate (—OSO₂O⁻), sulfonate(—SO₂O⁻), phosphate ((—O)₂P(O)O⁻ or —OP(O)(O⁻)₂), or carboxylate (—CO₂⁻); M is hydrogen (H⁺), sodium (Na⁺), potassium (K⁺), lithium (Li⁺),ammonium (NH₄ ⁺), calcium (Ca⁺²), magnesium (Mg⁺²), or R″A⁺, wherein R″is hydrogen or an alkyl or cycloalkyl group of about 1 to 10 carbonatoms, and A⁺ is selected from the group consisting of N⁺(R)₃ (e.g.,R″A⁺ can be N⁺(CH₃R)₄, HN⁺(CH₂CH₂OH)₃, H₂N(CH₂CH₂OH)₂) or a heterocyclic—N⁺B wherein B comprises 3 to 7 atoms selected from the group consistingof carbon, nitrogen, sulfur and oxygen atoms which complete thenitrogen-containing heterocyclic ring and satisfy the valence on thenitrogen atom; and wherein R is the same as R″ and may also besubstituted in available positions with oxygen, nitrogen or sulfuratoms; a and c are independently 1 or 2; b and d are independently 1, 2or 3; and e is equal to (c times d)/b.

[0172] Nonlimiting examples of preferred emulsifiers from the anionicclass of emulsifiers suitable for use in a thickener system of theinvention include behenic acid available as Croacid B from Croda, Inc.;stearyl phosphate available as Sippostat 0018 from Specialty IndustrialProducts, Inc. of Spartanburg, S.C.; and sodium stearate available fromCrompton Corp..

[0173] Class 13. Sorbitan Fatty Acid Esters

[0174] where R₆ is as defined above in Emulsifier Class 3, R₁₃ is H or—C(O)R₆ and each v is independently 0-30.

[0175] Fatty acid esters of sorbitan and its polyethoxylatedderivatives, polyoxyethylene derivatives of mono and poly-fatty estersare also examples of additional emulsifiers useful in the presentinvention.

[0176] Certain combinations of the above-listed emulsifiers are usefulin some preferred embodiments to form viscous stable thickener systemsof the present invention. These preferred systems are listed below.Nonlimiting Examples of Suitable Thickener Systems: System # Emulsifier1/(Class)* Emulsifier 2/(Class)* Emulsifier 3/(Class)* Emulsifier4(Class)* 1 Alkyl polyglucoside (1) polyethoxylated alkyl alcohol (8)quaternary amine (5) 2 alkyl polyglucoside (1) polyethoxylated alkylalcohol (8) amine Oxide (7) 3 alkyl polyglucoside (1) tertiary amine (6)4 alkyl polyglucoside (1) quaternary amine (5) 5 polyglycerol ester (4)polyethoxylated alkyl alcohol (8) alkyl alcohol (3) 6 polyglycerol ester(4) polyethoxylated alkyl alcohol (8) alkyl alcohol (3) alkyl ester (2)7 polyglycerol ester (4) polyethoxylated alkyl alcohol (8) quaternaryamine (5) 8 polyglycerol ester (4) alkyl ester (2) quaternary amine (5)9 polyglycerol ester (4) amine oxide (7) quaternary amine (5) 10alkyl/alkenyl alcohol (3) alkyl ester (2) quaternary amine (5) 11alkyl/alkenyl alcohol (3) alkyl ester (2) amine oxide (7) 12 alkyl ester(2) polyethoxylated alkyl alcohol (8) quaternary amine (5) 13 alkylbetaine (7) polyethoxylated alkyl alcohol (8) 14 alkyl phospholipid (9)polyethoxylated alkyl alcohol (8) 15 alkyl ester (2) alkyl alcohol (3)dialkoxydimethicone 16 hydroxyfunctional ester (2) polyethoxylatedalcohol (8) 17 hydroxyfunctional ester (2) alkyl alcohol (3) quaternaryamine (5) 18 hydroxyfunctional ester (2) quaternary amine (5) 19polyglycerol ester (4) polyethoxylated alkyl alcohol (8) 20 alkylcarboxylate (12)  polyethoxylated alkyl alcohol (8)

[0177] It is a simple matter to test certain combinations of emulsifiersto determine if they provide a suitable thickener system. Screeningmethodology is set forth in the Examples. The examples illustrate theimportance of the head group size with respect to the ratio of the mixedemulsifiers required to produce a stable emulsion. For example, systemsbased on a C16/C18 alkyl polyglucoside combined with C18 polyethoxylatesof varying level of ethoxylation (BRIJ) produce stable emulsions atwidely varying ratios.

[0178] Without intending to be bound by theory, the physical structureof the compositions used in the methods of the present invention isbelieved to be that of an emulsion. A classic definition of an emulsionis a stable dispersion of one liquid in a second immiscible liquid.However, as stated earlier, the present composition is preferably formedusing at least one emulsifier that is a solid wax at room temperature.The compositions described herein are believed to be a viscous stablemixture of a solid, semisolid, or liquid phase in a second liquid phase.It is believed that if certain hydrophobic emollients are added to thecompositions, hydrophobic emulsifiers and immiscible emollients form an“oil” or hydrophobic phase which is dispersed in the hydroalcoholicliquid phase to form an “oil” in “water” emulsion. The hydroalcoholicphase is referred to herein as the “water” phase. Since many preferredemulsions are somewhat viscoelastic, these emulsions are believed to beliquid crystalline emulsions that have been cooled below thecrystallization temperatures of the chosen emulsifiers to form asemi-crystalline gel-like network. Certain formulations may be simplyswollen crystalline precipitates forming a strongly interacting networkin the hydroalcoholic phase (so called coagel phase). The compositionsdescribed herein may also exist as combinations of these structures.Liquid crystalline and coagel phases in aqueous systems are described in“Application of Emulsion Stability Theories to Mobile and Semisolid O/WEmulsions,” Cosmetics and Toiletries, Vol. 101, pp 73-92 (1986), and“Influence of Long Chain Alcohols (or Acids) and Surfactants on theStability and Consistencies of Cosmetic Lotions and Creams,” Cosmeticsand Toiletries, Vol. 92, pp. 21-28 (1977) both of which are herebyincorporated by reference. The exact type of molecular association thatoccurs depends on many factors including the nature, size, and physicaland chemical states of the polar and hydrocarbon portions of theemulsifiers that form the thickener system at a specified temperature.

[0179] Certain of these liquid crystalline or coag gel phases interactwith light in such a way as to provide a pearlescent or opalescentappearance. The resulting rainbow effect aesthetically enhances theappearance of the formulation without added dyes or pigments.

[0180] Emulsifiers other than those required in the composition toprovide a thickener system may also be added as emollients orstabilizers. These emulsifiers are referred to herein as auxiliaryemulsifiers. For example, certain emollients are also comprised ofhydrophobic and hydrophilic regions and are useful in the presentinvention since they are believed to become incorporated into the liquidcrystalline network. These emollients tend to enhance the stability ofthe composition as is discussed more fully below. Furthermore, certaindimethicone copolyol surfactants can actually improve the stability offormulations incorporating emollients. This is also discussed in moredetail below.

Optional Ingredients

[0181] In addition to alcohol, water and thickener system, thecompositions of the present invention may optionally include ingredientssuch as salts, emollients, stabilizers, antimicrobials, fragrances,therapeutic agents, propellants and additional emulsifiers. Each ofthese optional ingredients along with the effect each has upon theproperties of the final composition is discussed below.

[0182] Salts

[0183] The melt temperature of the compositions used in the methods ofthe present invention may be increased by adding salts. As theconcentration of salt is increased, the ratio of emulsifiers will oftenneed to change in order to maintain a stable composition. It isimportant to choose salts that do not create an unstable system.

[0184] Stabilizers

[0185] A stable composition is one that does not separate more than 10%by volume after centrifuging at 2275×g for 20 minutes as measured at thelongitudinal midpoint of the sample tube. It is also recognized thatstability may be time dependent due to crystallization of emulsifiersand/or emollients present in the system, coalescence of emollients,emulsifiers and the like and, therefore, preferred compositions do notexhibit separation of more than 10% after standing for 6 months atambient conditions. Two types of stabilizers are useful in the presentinvention. These include (1) those stabilizers that complex withemulsifier hydrophilic head groups, and (2) those that associate withthe emulsifier hydrophobic tails. Certain stabilizers may perform bothfunctions. For example, emulsifiers comprising 1,2 diol-containing headgroups such as alkylpolyglucosides, monoalkylglycerides, andpolyglycerol alkyl esters, may be “stabilized” by adding borate ion.Without intending to be bound by theory, it is believed that borate ionscomplex with adjacent head groups which may increase the association ofhydrophobic tails by holding them in close proximity. Natural orsynthetic polymers comprised of pendent long chain alkyl groups (greaterthan 12 and preferably greater than 16 carbon atoms) such as stearylmodified cellulose derivatives, stearyl modified proteins such as wheatprotein, stearyl modified collagen and the like are capable ofstabilizing compositions of the present invention. Such added componentsmay also increase the melt temperature of compositions of the presentinvention. It is believed that the pendent alkyl groups in thesepolymers associate by Van der Waals interactions with the hydrophobes ofa thickening system, thereby enhancing the stability of the crystallinestructure. Polymeric thickeners that do not have associative pendentalkyl chains may also increase the melt temperature presumably byincreasing the viscosity of the continuous phase. A nonlimiting exampleof such thickeners are quaternary celluloses such as CELQUAT 230M asavailable from National Starch of Bridgewater, N.J. In a preferredembodiment stearyldimonium hydroxypropyl cellulose commerciallyavailable as CRODACEL QS from Croda Inc., Parsippany, N.J. is added as astabilizer.

[0186] Emollients

[0187] Emollients are typically added to hand and body lotions becausethey act to increase the moisture content of the stratum corneum.Emollients are generally separated into two broad classes based on theirfunction. The first class of emollients function by forming an occlusivebarrier to prevent water evaporation from the stratum corneum. Thesecond class of emollients penetrate into the stratum corneum andphysically bind water to prevent evaporation. The first class ofemollients is subdivided into compounds that are waxes at roomtemperature and compounds that are liquid oils. The second class ofemollients includes those that are water soluble and are often referredto as humectants.

[0188] For the purposes of this invention the thickener system isconsidered separate and distinct from any emollients which may be addedeven though it is recognized that the emulsifiers may function asocclusive emollients and aid in maintaining or improving the skincondition. Emollients are included in a preferred embodiment of theinvention and preferably comprise between about 3 and 30%, morepreferably between about 4 and 20% and most preferably between about 5and 12% by weight of the formulation.

[0189] The ratio of wax to liquid emollients (oils and humectants) in apreferred embodiment of the invention is between about 5:1 to 1:5 andpreferably between about 1:3 to 3:1. Also, the ratio of wax emollientsand wax emulsifiers to liquid emollients and liquid emulsifiers in apreferred embodiment of this invention is from about 1:5 to about 5:1,and more preferably, from about 1:3 to about 3:1. Emollients may beselected from any of the classes known in the art. A general list ofuseful emollients appears in U.S. Pat. No. 4,478,853 and EPO patentapplication 0 522 624 A1 and in the CTFA Cosmetic Ingredient Handbookpublished by The Cosmetic, Toiletry, and Fragrance Association, Wash.D.C. (1992) under the listings “Skin Conditioning Agents,” “Emollients,”“Humectants,” “Miscellaneous” and “Occlusive.”

[0190] In preferred embodiments, emollients are chosen from thefollowing nonlimiting list of general emollients, occlusive emollientsand humectants. Examples of general emollients include short chain alkylor aryl esters (C1-C6) of long chain straight or branched chain alkyl oralkenyl alcohols or acids (C8-C36) and their polyethoxylatedderivatives; short chain alkyl or aryl esters (C1-C6) of C4-C12 diacidsor diols optionally substituted in available positions by —OH; alkyl oraryl C1-C9 esters of glycerol, pentaerythritol, ethylene glycol,propylene glycol, as well as polyethoxylated derivatives of these andpolyethylene glycol; C12-C22 alkyl esters or ethers of polypropyleneglycol; C12-C22 alkyl esters or ethers of polypropyleneglycol/polyethylene glycol copolymer; and polyether polysiloxanecopolymers. In addition to many of the emulsifiers of preferredthickener systems, additional examples of occlusive emollients includecyclic dimethicones, polydialkylsiloxanes, polyaryl/alkylsiloxanes, longchain (C8-C36) alkyl and alkenyl esters of long straight or branchedchain alkyl or alkenyl alcohols or acids; long chain (C8-C36) alkyl andalkenyl amides of long straight or branched chain (C8-C36) alkyl oralkenyl amines or acids; hydrocarbons including straight and branchedchain alkanes and alkenes such as squalene, squalane, and mineral oil;polysiloxane polyalkylene copolymers, dialkoxy dimethyl polysiloxanes,short chain alkyl or aryl esters (C1-C6) of C12-C22 diacids or diolsoptionally substituted in available positions by OH; and C12-C22 alkyland alkenyl alcohols. Nonlimiting examples of preferred humectant typeemollients include glycerol, propylene glycol, dipropylene glycol,polypropylene glycol, polyethylene glycol, sorbitol, pantothenol,gluconic acid salts and the like.

[0191] Although a thickener system is responsible for the stability andoverall consistency of compositions of the present invention, emollientsmay also affect the viscosity, stability, and melt temperature of acomposition. It is anticipated that a single emollient may be added tothe present invention or two or more emollients may be added to thecomposition. A wide range of emollients may be added to the formulationsof the present invention. Preferably wax and oil type emollients alongwith water soluble emollients are used. In a preferred embodiment,emollient systems are comprised of humectants in addition to occlusivewax and oil emollients in concentrations which achieve a moisturizingbut not greasy composition which maintains and improves the condition ofthe skin upon repeated use. Preferably, emollients are non-comedogenic,non-acnegenic, and are chosen to ensure no skin irritation orsensitization reaction occurs.

[0192] Without being bound or limited by theory, it is believed that ifemollients are added to the present compositions, they may be present infour distinct regions. The emollients could occur (1) as a solublespecies in the solvent phase, (2) dispersed as emulsified dropletswithin the mixed emulsifier micelle or crystalline gel network, (3)incorporated into the mixed emulsifier micelle or crystalline gelnetwork, or (4) as a separate and distinct emulsion. As earlier stated,emollients can affect the melt temperature of a composition. Thoseemollients that are soluble or dispersible in the solvent phase tend tohave little or no affect on the melt temperature and are thereforepreferred. These emollients include the humectant and generalemollients. The most preferred general emollients are those which areessentially insoluble in water but soluble in the hydroalcoholicsolvent. These emollients are also preferred since they remain solubleand uniformly dispersed even above the melt temperature so that uponcooling to room temperature a uniform composition results. Such generalemollients typically do not have alkyl or alkenyl chains greater thanabout 14, preferably not greater than 12 and most preferably not greaterthan about 9 carbon atoms.

[0193] Those emollients which are insoluble in the hydroalcoholicsolvent may associate with the emulsifiers of the thickener systemand/or become incorporated into the micelle or crystalline gel network.Preferred emollients within this class are those emollients that arevery hydrophobic since they tend to maintain a high melt temperature.For example, hexadecane was found to increase the viscoelasticity ofcertain thickener systems. Those emollients which are capable ofassociating with and disrupting the emulsifiers of the thickener systemtend to decrease the melt temperature and may influence the stability ofthe composition. Certain branch alkyl esters of greater than about 12carbon atoms per hydrophobe have been found to be particularly effectiveat decreasing the melt temperature. For example, trioctyldodecyl citratehas been found to significantly decrease the melt temperature of somesystems.

[0194] Emollients which become incorporated into the thickener systemtend to decrease the melt temperature. For example, laureth-4 (BRIJ 30)appears to incorporate into the thickener system since it does not phaseout when heated above the melt temperature at concentrations below about1% by weight. Laureth-4 also tends to decrease the melt temperature ofthe composition.

[0195] Certain emollients which are insoluble in the hydroalcoholicsolvent can be emulsified in what is believed to be a separate anddistinct emulsion. These emollients have little affect on the melttemperature of a composition. For example, certain cyclic silicones,polysiloxanes, and dialkoxypolysiloxanes can be emulsified inhydroalcoholic solvents using polyether/polysiloxane copolymerssurfactants. Cyclic silicones such as DC344 (available from Dow Corningof Midland, Mich.) in the presence of certain polyether/polysiloxanecopolymers such as ABIL B88183 available from Goldschmidt Chemical Corp.of Hopewell, Va., can form a thermally stable emulsion such that thecompositions remain uniform both above and below the melt temperature.In fact, the combination of a long chain dialkoxypolysiloxane andpolyether/polysiloxane copolymer has been found to actually promote thestability of certain thickener systems. The dialkoxypolysiloxane isbelieved to interact with the thickener system as well as thepolyether/polysiloxane copolymer. These compounds have the followingstructures:

[0196] Dialkoxy Dimethicones

R—O—Si(CH₃)₂—O[Si(CH₃)₂—O]_(z)—Si(CH₃)₂—OR

[0197] where R is a straight chain alkyl group of 14-50, preferably16-24 carbon atoms, and

z=5-300

[0198] Polyether/Polysiloxane Copolymers (Dimethicone Copolyols)

(CH₃)₃—Si—O—[Si(CH₃)R₁₁—O]_(x)[Si(CH₃)R₈—O]_(y)—Si(CH₃)₃

[0199] where

[0200] x+y=5-400, preferably 15-200, and

[0201] R₈ is a polyether substituted alkyl group with the structure:

—R₉—O(C₂H₄O)_(p)(C₃H₆O)qR₁₀;

[0202] where

[0203] R₉ is an alkyl group of 1 to 6 carbon atoms;

[0204] R₁₀ is hydrogen or an alky group of 1-22 carbon atoms;

[0205] R₁₁ is an alkyl group of 1 to 22 carbon atoms or phenyl;

[0206] p=2-300, preferably 8-100; and

[0207] q=0-100.

[0208] Note that branched chain polysiloxanes modified as shown in thetwo structures above are also possible.

[0209] The following are nonlimiting examples of emulsifier/emollientcomponents which improve thickening/stability of compositions of thepresent invention.

[0210] a. Certain wax emulsifiers/emollients have been found to beparticularly useful and include solid waxy esters such as: MyristylMyristate, Cetyl Palmitate, Myristyl Stearate, Stearyl Behenate, BehenylIsostearate, Isostearyl Behenate, Behenyl Behenate, Lauryl Behenate,Behenyl Erucate. These have the following formula:

R₁—CO₂—R₂

[0211] where:

[0212] R₁ is at least 14 carbon atoms; and

[0213] R₂ is an alkyl or alkenyl of at least 4 carbon atoms.

[0214] b. Long chain hydrocarbon di-esters, tri-esters, of polyhydricalcohols with melting point greater than 23° C. include solid esterssuch as glycerol tribehenate and sorbitan tristearate.

[0215] c. Pure lanolins and lanolin derivatives (e.g. hydrogenatedlanolin) provide excellent emolliency and can also improve the stabilityof the emulsion when used in combination with oil emollients.

[0216] d. Petrolatums provide excellent emolliency and can also improvethe stability of the emulsion when used in combination with oilemollients. Petrolatums are mixtures of oily and waxy long chainhydrocarbons.

[0217] e. Microcrystalline waxes and branched hydrocarbon waxes with amelting point greater than 50° C. and a molecular weight greater than400. An example of this includes but is not limited to VYBAR 103 whichis a branched hydrocarbon with a number average molecular weight of 2800and is available from Petrolite Corp. of Tulsa, Okla. and ULTRAFLEXwhich is a microcrystalline wax also available from Petrolite Corp.

[0218] f. Oxidized waxes and modified hydrocarbon waxes may findapplication in the present invention. These are prepared from waxesmodified by oxidation, salts of oxidized waxes, maleic anhydride adductsof polyolefins and urethane derivatives of oxidized synthetic orpetroleum waxes. Applicable waxes could include Petrolite's Cardis orPetronauba microcrystalline and polyethylene-based oxidized products,Polymekon (salts) and Ceramer (anhydride adducts).

[0219] g. Fully saturated homopolymers of polyethylene or copolymers ofvarious alkene monomers may be used to form polymers with a molecularweight at or below 3,000 with a melting point below 130° C. and low meltviscosities. Applicable waxes could include POLYWAX available fromPetrolite Corp.

[0220] Fragrances

[0221] The formulations may also include a fragrance. If fragrances areincluded the fragrances must be chosen carefully since some fragrancesare known to cause skin irritation and/or sensitization reactions.

[0222] One or more fragrances can be used in compositions of thisinvention in amounts ranging from about 0.5 to about 8%, preferably fromabout 1 to about 4% by weight. A fragrance formulation may include suchcomponents as C10-C30 terpenes, C5-C50 aldehydes, C5-C50 ketones, C5-C50esters and combinations thereof. Preferred fragrances are liquids atroom temperature and are relatively volatile having a closed cupflashpoint of less than 120 C and preferably less than 95 C when testedaccording to ASTM D-56 “Standard Method for Flashpoint by Tag ClosedTester.” The following is a list of illustrative specific fragrancecomponents: iso-amyl salicylate, carvacrol, clove leaf oil, ethylsalicylate, iso-eugenol, hexyl salicylate, thyme oil red, geraniol,limonene, 6-acetyl-1,1,3,4,4,6-hexamethyl-tetrahydronaphthalene,p-t-amyl cyclohexanone, 2-n-heptylcyclo-pentanone, a-iso-methyl ionone,beta-methyl naphthyl ketone, iso-butyl quinoline, methyl anthranilate,o-t-butylcyclohexyl acetate, p-t-butylcyclohexyl acetate, diethylphthalate, nonanediol-1,3-diacetate, nonanolide-1,4, i-nonyl acetate,i-nonyl formate, cyclopentane, tetrahydromuguol, cedar wood oil, geranylphenylacetate, guaiacwood oil, linalyl benzoate, phenyl ethyl alcohol,dihydromyrcenol, linalool, isolongifolanone, hexyl cinnamic aidehyde,linalyl acetate, citronellyl acetate, phenyl ethyl acetate, acetyltributyl citrate, benzyl salicylate, isobutyl cinnamate, linalylcinnamate, coumarin, acetyl cedrene, allyl amyl glycolate, vanillin,patchouli oil, bergamot oil, citronellol, and combinations thereof. Thenomenclature adopted for the components listed above, so far aspossible, is that employed by Steffan Arctander in “Perfume and FlavorChemicals (Aroma Chemicals)” Volume I and II (1969) and the “Perfume &Flavor Materials of Natural Origin” (1960) by the same author.

[0223] Foams

[0224] The compositions used in the methods of the present invention mayalso be formulated into an aerosol foam or mousse by addition of anappropriate propellant. The propellant must be chosen to ensure properdelivery from the container to prevent clogging of the valve. Thepropellant can be chosen from chlorofluorocarbons (CFCs),hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs),perfluorinated alkanes, and lower alkanes (C1-C5) as well as nitrousoxide dimethyl ether and other solvent-soluble propellants. Preferredpropellants are lower alkanes such as propane, butane, and isobutanesince these result in a dramatic loss in viscosity making theformulation easy to dispense. A 70/30 mixture of propane/isobutane is aparticularly preferred embodiment. In order to produce an aerosolcomposition the lotion is first formulated and charged into anappropriate pressure rated container. If convenient, the formulation maybe heated above the melt temperature in order to facilitate filling. Thepropellant is then added under pressure at approximately 2-30%preferably 3-20% by volume. The propellant may form a separate layer ormay remain emulsified in the composition.

Methods of Preparation

[0225] The compositions used in the methods of the present invention maybe prepared by a variety of techniques. For example, the process canoften be as simple as adding the thickener system to the hydroalcoholicsolvent at a temperature above the melting point of the emulsifiers,mixing briefly and cooling. Nevertheless, to ensure a composition ofmaximum stability the components are preferably subjected to high shear(e.g. homogenized) for a limited time period while above the meltingpoint of the thickener system followed by low shear mixing whilecooling. The system should be mixed under high shear long enough toensure a very small “droplet” size, however, excessive high shear mixingmay result in decreased viscosity and stability.

[0226] The cooling rate may be important depending on the particularthickener system. Certain thickener systems can be homogenized and thenallowed to cool slowly, however, rapid cooling appears beneficial formost systems.

[0227] The order of adding the components may also affect the stabilityand viscosity of the system. In general it works well to melt the mixedemulsifiers with aqueous-insoluble emollients together in one vessel.The hydroalcoholic solvent and any aqueous miscible emollients are mixedin a second vessel. Both components are heated above the meltingtemperature of the thickener system. The hot liquid components are mixedtogether rapidly followed by approximately 1 to 5 minutes ofhomogenization for typical batches under 500 grams. While still low inviscosity the system is stirred using moderate agitation and cooled. Itis also possible to add the molten thickener system along with anysolvent insoluble emollients to hot water (i.e., water at a temperatureabove the melting temperature) followed by high shear mixing andsubsequent dilution with alcohol. The processing variables includingamount and intensity of high shear mixing, rate of cooling, and order ofaddition are easily determined by one skilled in the art.

Test Methods

[0228] Viscosity

[0229] In the following Examples (except where indicated) viscosity wasmeasured at 23° C. at ambient pressure using a Brookfield LVDV-I⁺viscometer equipped with a model D Brookfield heliopath and T spindlesB-F. The spindle and speed was chosen for each particular sample suchthat the viscometer was operating in the middle of its range. Allsamples were allowed to equilibrate at 23° C. for 24 hours prior tomeasurement. Preferably the viscosity is taken at the lowest speedpossible while staying within 20-80% of the viscometer range and morepreferably between 30-70% of the range. In all cases the sample size andcontainer geometry was chosen to ensure that there were no wall effects.By “wall effects” it is meant the viscosity value is not affected by thecontainer and is essentially equivalent to the viscosity taken in aninfinitely large container. For this reason lower viscosity samplesrequired a larger sample size to accommodate the larger spindles. Thefollowing table outlines preferred spindles for various sampleviscosities. Sample Viscosity T Spindle to Use  1,000-100,000 B10,000-200,000 C 50,000-500,000 D 100,000-1,250,000 E 500,000-3,000,000F

[0230] The viscosity of each sample was taken as the highest relativelystable reading achieved on the first path the spindle traversed usingthe heliopath adapter.

[0231] Stability

[0232] The stability of samples was measured 24 hours after conditioningat ambient conditions by placing 12 ml of a formulation that formed alotion/cream in a 15 ml graduated centrifuge tube. The tube was thencentrifuged in a Labofuge B (Heraeus Sepatech GmbH, Model 2650, rotor2150 and buckets #2101) at 3000 rpm (2275×g when measured at thelongitudinal midpoint of the sample tube) for 20 minutes at 23° C.Stability is recorded as a volume percent separation in the Examplesbelow.

[0233] Melt Temperature (Tm)

[0234] The melt temperature was measured by placing approximately 15grams sample in a 25 cubic centimeter (cc) sealed glass vial and placingthe vial in a water bath. The temperature of the bath was increasedperiodically in discrete increments and the contents checked afterapproximately 1 hour at a given temperature. The melt temperature wastaken as the temperature at which the mixture became very low inviscosity.

[0235] Cosmetic Properties/Tactile Testing

[0236] For use in aftershaves the compositions of this invention arepreferably formulated with emollients to achieve a moisturized butrelatively dry feel. Compositions with excessive emollients tend to beperceived as greasy. The formulations of this invention do not provide atacky or sticky feel even in high humidity environments throughout theapplication process. The invention formulations preferably yield asmooth, soft, nontacky, and moisturized feeling. Testing of the cosmeticor tactile properties of the compositions was conducted with preferablygreater than ten evaluators who applied a premeasured amount of product,approximately 2 ml. Since hand washing can affect the feel of thecompositions, evaluators washed thoroughly with IVORY Skin CleansingLiquid Gel hand soap available from Procter and Gamble, Cincinnati, Ohiobefore applying the sample. After drying, the composition was rubbeduniformly over the surfaces of both hands until the composition was dry.The feel of the composition on the skin during subsequent washing withsoap and water was also important. Approximately 30-60 minutes afterapplication of the composition the feel during subsequent washing wasevaluated. Preferred formulations did not result in an abnormal feelingsuch as slimy, slippery, or sticky characteristics.

EXAMPLES

[0237] The following Examples are provided to illustrate the inventionand are not intended to limit the scope of the invention.

Examples 1-20

[0238] The following after-shave lotion formulations were prepared usingthe compounds listed below in the percentages indicated in Table 1.TABLE 1 Amount of ingredients in formulations No 0.25% 0.50% In-Fragrance Fragrance Fragrance gredient Wt. Wt. Wt. Number IngredientPercent Percent Percent Part A  1 Beheneth Ether¹ (BB-10) 1.50 1.50 1.50 2 UNITHOX 470² 0.25 0.25 0.25  3 Behenyl Alcohol³ (BE-22) 1.10 1.101.10  4 Cetyl Palmitate⁴ 0.05 0.05 0.05  5 Diisopropyl Dimerate⁵ 1.001.00 1.00  6 Squalane⁶ 1.00 1.00 1.00  7 DIMETHICONE 0.50 0.50 0.50LA5/350⁷  8 Miconazole nitrate⁸ 2.00 2.00 2.00 Part B  9 PolyethyleneGlycol 900⁹ 0.95 0.95 0.95 10 Polyethylene Glycol 600¹⁰ 0.30 0.30 0.3011 Glycerol¹¹ 0.45 0.45 0.45 12 Purified Water 29.088 29.008 28.928 Part13 Ethyl Alcohol¹² 61.812 61.642 61.472 Part 14 Fragrance¹³ 0.000 0.2500.500

[0239] Each formulation was prepared by placing the ingredients of PartA into a 200 ml glass jar and heating to 90° C. for an hour to melt theemulsifiers with constant stirring. If the emulsifiers were not melted,a heat gun was applied with constant stirring. At the same timeingredients of Part B were placed into another 200 ml glass jar andheated to 85° C. for an hour. Next Part B was added to Part A and themixture was sheared on a Silverson homogenizer at high (100%) speed forone minute. The glass jar was sealed with a screw cap and heated to 56°C. for approximately one hour. This was cooled while rolling slowly onits side for approximately one hour. Part C was placed in a 200 ml jarand slowly added to the cooled combined formulation and shakenvigorously by hand for 60 seconds or until homogenous. The entireformulation was sheared again on the homogenizer at high speed (100%)for one minute. The steps of shaking and shearing were repeated. Thiswas allowed to cool and the formulation was centrifuged by placing it ina 250 ml centrifuge bottle and spinning at low speed, e.g., less than500 rpm to remove air bubbles.

[0240] Twenty formulations were prepared using 5 different fragrances(Part D) at two levels of concentration (0.25% and 0.50%) and addingeach at different times in the preparation of the emulsion either beforeaddition of component of Part C (Pre) or after the emulsion wascompletely made (post). In the latter case the fragrance was added andmixed in by vigorous shaking by hand. Table 2 contains a list of thefragrances and their descriptions. TABLE 2 Description of FragrancesNumber Fragrance Chemical Nature EXP 29980 Grape aldehydes and esters FG0540 Tea rose fragrance alcohols FG 0124 Synthetic spearmint HydrophobicFG 0653 Lemon terpenic hydrocarbons FG 9494 Water soluble lemonHydrophilic

[0241] The stability of samples was measured after conditioning 24 hoursat ambient conditions following the procedure described under Stabilityand recorded in Table 3. As used in Table 3 “trace” means that there wasa slight settling on the bottom of the tube but this was less than 0.1ml. TABLE 3 Results of the Stability Test Example Fragrance Before orAfter Fragrance Percent Number Number Component C (Wt. Percent)Separation 1 FG0653 Post 0.50 Trace 2 FG0124 Post 0.50 Trace 3 FG0540Post 0.50 Trace 4 EXP29980 Post 0.50 Trace 5 FG9494 Post 0.50 Trace 6FG0653 Post 0.25 Trace 7 FG0124 Post 0.25 Trace 8 FG0540 Post 0.25 Trace9 EXP29980 Post 0.25 Trace 10 FG9494 Post 0.25 Trace 11 FG0653 Pre 0.25Trace 12 EXP29980 Pre 0.25 Trace 13 FG0540 Pre 0.25 None 14 FG9494 Pre0.25 None 15 FG0124 Pre 0.25 None 16 FG0540 Pre 0.50 Trace 17 EXP29980Pre 0.50 Trace 18 FG9494 Pre 0.50 Trace 19 FG0653 Pre 0.50 None 20FG0124 Pre 0.50 Trace

[0242] The results indicated that all of the fragrances produced stableemulsions. The wide variety of chemical functionality on the fragrancesdid not appear to effect the stability at the concentrations used. Theformulations left a pleasant characteristic odor when dry. These samplesdemonstrate the use of both an antimicrobial agent and a fragrance.Similar results would be expected without the antimicrobial agent(miconazole nitrate). These formulations are useful in a broad range ofcosmetic products applied to the skin including shaving creams, gels,and lotions as well as after shave creams, lotions, and gels for usebefore, during or after removal of both facial and non-facial hair. Theformulations could also be supplied in the form of a mousse byintroduction of a propellant as described previously.

Example 21

[0243] Alkyl Alcohol/Quaternary Amine Thickener System

[0244] The following formulations were prepared using LANETTE 22 (HenkelCorp of Ambler, Pa.), behenyl alcohol available under the tradedesignation NIKKOL CA-2580 (Barnet Products Corp., Paterson, N.J.),behenyltrimethyl ammonium chloride Composition Component A B C Amount(grams) NIKKOL CA-2580 0.59 0.59 0.44 LANETTE 22 1.5 2.00 1.63 68:32Ethanol:water 47.91 47.41 47.93

[0245] The compositions were prepared by separately heating the solventand the thickener system to 65-70° C. The solvent was rapidly added tothe thickener system followed by stirring with an overhead paddlestirrer with the glass container immersed in a 10° C. water bath. Eachcomposition was mixed for 4.5 minutes after which the compositionscooled sufficiently for the emulsifiers to solidify.

[0246] All three compositions were viscoelastic. The samples appearedpearlescent with macroscopically obvious crystalline regions. Thecrystals appeared macroscopically lamellar in nature. A small amount ofsyneresis was seen on standing at 23° C. overnight. The Tm of sample Cwas approximately 47° C. (The sample did not melt uniformly and even at47° C. still had some solid regions.)

[0247] While in accordance with the patent statutes, description of thepreferred weight fractions, processing conditions, and product usageshave been provided, the scope of the invention is not intended to belimited thereto or thereby.

[0248] Various modifications and alterations of the present inventionwill be apparent to those skilled in the art without departing from thescope and spirit of the present invention. The Examples described inthis application are illustrative of the possibilities of varying thetype, quantity and ratio of composition as well as the methods formaking formulations of the present invention. The complete disclosuresof all patents, patent applications, and publications recited herein areincorporated by reference, as if individually incorporated by reference.

What is claimed is:
 1. A method of reducing skin irritation associatedwith shaving, the method comprising applying to skin a compositioncomprising: a) a lower alcohol and water in a weight ratio of about20:80 to 100:0, and b) about 0.5% to about 8% by weight of a thickenersystem, based on the total weight of the composition, wherein thethickener system comprises at least about 0.05% by weight of at leastone emulsifier, based on the total weight of the composition, whereinthe emulsifier comprises: (i) at least one hydrophobic group selectedfrom the group consisting of: A. an alkyl group of at least 16 carbonatoms; B. an alkenyl group of at least 16 carbon atoms; and C. anaralkyl or an aralkenyl group of at least 20 carbon atoms; and (ii) atleast one hydrophilic group selected from the group consisting of: A. anethylene oxide- and/or propylene oxide-containing group bonded to thehydrophobic group through an ether or ester bond and optionallyterminated with a (C1-C36)alkyl ester, (C2-C36)alkenyl ester, or(C6-C36)alkaryl ester; B. an alcohol group; C. a polyhydric alcoholgroup; D. an ester or ether group of a polyhydric alcohol orpolyalkoxylated derivative thereof having 2-150 moles of alkylene oxideper mole of hydrophobic group; E. an ester or ether group of sorbitan orpolyalkoxylated derivative thereof; and F. combinations of these groups;wherein the composition has a viscosity of at least about 4,000centipoise at 23° C. when in the absence of an auxiliary thickener, asmeasured using a very low shear viscometer and T spindles with aheliopath adapter.
 2. The method of claim 1 wherein the hydrophobicgroup is selected from the group consisting of: an alkyl group of atleast 24 carbon atoms; an alkenyl group of at least 24 carbon atoms; andan aralkyl or an aralkenyl group of at least 24 carbon atoms.
 3. Themethod of claim 1 wherein the composition has a melt temperature ofgreater than about 25° C. when in the absence of an auxiliary thickener.4. The method of claim 1 wherein the composition does not separate morethan about 10% by volume when centrifuged for 20 minutes at 2275×g. 5.The method of claim 1 wherein the thickener system has a weight averagehydrophile/lipophile balance of about 8 to about
 12. 6. The method ofclaim 1 wherein the lower alcohol to water weight ratio is about 60:40to about 75:25.
 7. The method of claim 1 wherein the composition furthercomprises at least one emollient distinct from the thickener system. 8.The method of claim 1 wherein the composition further comprises a salt.9. The method of claim 1 wherein the composition further comprises astabilizer.
 10. The method of claim 1 wherein the composition furthercomprises a polymeric thickening agent.
 11. The method of claim 1wherein the thickener system comprises at least one of the following: a)a polyethoxylated alcohol and an alkyl alcohol; b) a polyethoxylatedalkyl alcohol; c) a polyhydric alcohol ester and polyethoxylatedalcohol; d) an alkyl ester of sorbitan and a polyethoxylated alcohol; e)an alkyl alcohol and an alkyl ester of a polyethoxylated alcohol; f) apolyethoxylated alkyl alcohol and an alkyl ester of a polyethoxylatedalcohol; g) an alkyl alcohol, a polyethoxylated alkyl alcohol, and adimethicone copolyol alkyl phosphate; or h) a polyglycerol ester, apolyethoxylated alcohol, and an alkyl alcohol.
 12. The method of claim11 wherein the thickener system further comprises an emulsifier with atleast two hydrophobic components.
 13. The method of claim 12 wherein theemulsifier with at least two hydrophobic components is a quaternaryammonium salt.
 14. The method of claim 1 wherein the ethylene oxide-and/or propylene oxide-group is a polyethylene glycol group, apolypropylene glycol group, or a polyethylene glycol/polypropyleneglycol copolymeric group.
 15. The method of claim 1 wherein theemulsifier is selected from the group consisting of a poly(ethoxylatedand/or propoxylated) alcohol, a poly(ethoxylated and/orpropoxylated)ester, a derivative of a poly(ethoxylated and/orpropoxylated) alcohol, a derivative of a poly(ethoxylated and/orpropoxylated)ester, an alkyl alcohol, an alkenyl alcohol, an ester of apolyalkoxylated derivative of a polyhydric alcohol, an ether of apolyalkoxylated derivative of a polyhydric alcohol, a sorbitan fattyacid ester, a polyalkoxylated derivative of a sorbitan fatty acid ester,and mixtures thereof.
 16. The method of claim 1 wherein the compositionfurther comprises a fragrance.
 17. The method of claim 16 wherein thefragrance is a perfume.
 18. The method of claim 1 wherein thecomposition is pearlescent.
 19. The method of claim 1 wherein thecomposition is an aftershave.
 20. A method of reducing skin irritationassociated with shaving, the method comprising applying to skin acomposition comprising: a) a lower alcohol and water in a weight ratioof about 20:80 to 100:0, and b) about 0.5% to about 8% by weight of athickener system, based on the total weight of the composition, whereinthe thickener system comprises at least about 0.05% by weight of atleast one emulsifier, based on the total weight of the composition,wherein the emulsifier comprises: (i) at least one hydrophobic groupselected from the group consisting of: A. an alkyl group of at least 24carbon atoms; B. an alkenyl group of at least 24 carbon atoms; and C. anaralkyl or an aralkenyl group of at least 24 carbon atoms; and (ii) atleast one hydrophilic group selected from the group consisting of: A. anethylene oxide- and/or propylene oxide-containing group bonded to thehydrophobic group through an ether or ester bond and optionallyterminated with a (C1-C36)alkyl ester, (C2-C36)alkenyl ester, or(C6-C36)alkaryl ester; B. an alcohol group; C. a polyhydric alcoholgroup; D. an ester or ether group of a polyhydric alcohol orpolyalkoxylated derivative thereof having 2-150 moles of alkylene oxideper mole of hydrophobic group; E. an ester or ether group of sorbitan orpolyalkoxylated derivative thereof; and F. combinations of these groups;wherein the composition has a melt temperature of greater than about 25°C. and a viscosity of at least about 4,000 centipoise at 23° C. when inthe absence of an auxiliary thickener, as measured using a very lowshear viscometer and T spindles with a heliopath adapter.
 21. The methodof claim 20 wherein the composition further comprises a fragrance. 22.The method of claim 21 wherein the fragrance is a perfume.
 23. Themethod of claim 20 wherein the composition is pearlescent.
 24. Themethod of claim 20 wherein the composition is an aftershave.
 25. Amethod of reducing skin irritation associated with shaving, the methodcomprising applying to skin a composition comprising: a) a major amountof a solvent comprising a lower alcohol and water in a weight ratio ofabout 60:40 to 95:5, and b) about 0.5% to about 8% by weight of athickener system, based on the total weight of the composition, whereinthe thickener system comprises at least about 0.05% by weight of one ormore emulsifiers, based on the total weight of the composition, whereinat least one of the emulsifiers is solid at room temperature; whereinthe composition has a melt temperature of greater than about 25° C. anda viscosity of at least about 45,000 centipoise after 19 days at 23° C.when in the absence of an auxiliary thickener, as measured using a verylow shear viscometer and T spindles with a heliopath adapter.
 26. Themethod of claim 25 wherein the composition further comprises afragrance.
 27. The method of claim 26 wherein the fragrance is aperfume.
 28. The method of claim 25 wherein the composition is in theform of a lotion, a gel, or a foam.
 29. The method of claim 25 whereinthe composition comprises both wax and liquid emollients in a weightratio of 5:1 to 1:5 wax to liquid emollients.
 30. The method of claim 29wherein the weight ratio of wax to liquid emollients is within the range3:1 to 1:3.
 31. The method of claim 25 wherein the composition is anaftershave.
 32. A method of reducing skin irritation associated withshaving, the method comprising applying to skin a compositioncomprising: a) a lower alcohol and water in a weight ratio of about20:80 to 100:0, and b) about 0.5% to about 8% by weight of a thickenersystem, based on the total weight of the composition, wherein thethickener system comprises at least about 0.05% by weight of at leasttwo emulsifiers, based on the total weight of the composition, whereinat least one emulsifier comprises: (i) at least one hydrophobic groupselected from the group consisting of: A. an alkyl group of at least 16carbon atoms; B. an alkenyl group of at least 16 carbon atoms; and C. anaralkyl or an aralkenyl group of at least 20 carbon atoms; and (ii) atleast one hydrophilic group selected from the group consisting of: A. anethylene oxide- and/or propylene oxide-containing group bonded to thehydrophobic group through an ether or ester bond and optionallyterminated with a (C1-C36)alkyl ester, (C2-C36)alkenyl ester, or(C6-C36)alkaryl ester; B. an alcohol group; C. a polyhydric alcoholgroup; D. an ester or ether group of a polyhydric alcohol orpolyalkoxylated derivative thereof having 2-150 moles of alkylene oxideper mole of hydrophobic group; E. an ester or ether group of sorbitan orpolyalkoxylated derivative thereof; and F. combinations of these groups;and wherein at least one emulsifier comprises: (i) at least onehydrophobic group selected from the group consisting of: A. an alkylgroup of at least 16 carbon atoms; B. an alkenyl group of at least 16carbon atoms; and C. an aralkyl or an aralkenyl group of at least 20carbon atoms; and (ii) at least one hydrophilic group selected from thegroup consisting of: A. an amide group; B. a short chain ester of a longchain alcohol or acid; C. a polyglucoside group having 1-10 glucoseunits; D. a polyglycerol ester group having 1-15 glycerol units; E. asecondary amine group; F. a tertiary amine group; G. a anionic group; H.a zwitterionic group; and I. combinations of these groups.
 33. A methodof reducing skin irritation associated with shaving, the methodcomprising applying to skin a composition comprising: a) a lower alcoholand water in a weight ratio of about 20:80 to 95:5; and b) about 0.5% toabout 8% by weight of a thickener system, based on the total weight ofthe composition, wherein the thickener system comprises at least about0.05% by weight of at least one emulsifier, based on the total weight ofthe composition, wherein the emulsifier comprises: (i) at least onehydrophobic group selected from the group consisting of: A. an alkylgroup of at least 16 carbon atoms; B. an alkenyl group of at least 16carbon atoms; and C. an aralkyl or an aralkenyl group of at least 20carbon atoms; and (ii) at least one hydrophilic group selected from thegroup consisting of: A. an amide group; B. a short chain ester of a longchain alcohol or acid; C. a polyglucoside group having 1-10 glucoseunits; D. a polyglycerol ester group having 1-15 glycerol units; E. asecondary amine group; F. a tertiary amine group; G. a anionic group; H.a zwitterionic group; and I. combinations of these groups; wherein thecomposition has a viscosity of at least about 4,000 centipoise at 23° C.when in the absence of an auxiliary thickener, as measured using a verylow shear viscometer and T spindles with a heliopath adapter.
 34. Themethod of claim 33 wherein the zwitterionic group has the formula:—N⁺(R″)₂(CHQ)_(x)L′ or

wherein: each R″ is independently hydrogen, an alkyl group, an alkenylgroup, an alkyl carboxyl group, or an alkenyl carboxyl group, whichalkyl or alkenyl groups are optionally substituted with nitrogen,oxygen, or sulfur atoms; Q is hydrogen or hydroxyl; x is 1 to 4; and L′is —CO₂ ⁻, —OP(O)(O⁻)(O⁻M⁺), —(O)P(OR′″)(O)(O⁻M⁺), —SO₂O⁻M⁺ or —OSO₂O⁻M⁺wherein: R′″ is hydrogen or an alkyl group of 1-10 carbon atomsoptionally substituted with N, O, or S atoms; M⁺ is a positively chargedcounterion present in a molar ratio necessary to achieve a net neutralcharge on the emulsifier and is selected from the group consisting ofhydrogen, sodium, potassium, lithium, ammonium, calcium, magnesium,N⁺R″₄, and combinations of these groups.
 35. The method of claim 33wherein the thickener system has a weight average hydrophile/lipophilebalance of between about 8 and
 12. 36. The method of claim 33 whereinthe thickener system comprises at least one of the following: a) a shortchain ester of a long chain alcohol or acid, an alkyl or alkenylalcohol, and a quaternary amine; b) an alkylpolyglucoside, apolyethoxylated alcohol, and a quaternary amine; c) analkylpolyglucoside, a polyethoxylated alcohol, and an amine oxide; d) analkylpolyglucoside and a tertiary amine; e) an alkylpolyglucoside and aquaternary amine; f) a polyglycerol ester, a polyethoxylated alcohol,and an alkyl or alkenyl alcohol; g) a polyglycerol ester, apolyethoxylated alcohol, an alkyl or alkenyl alcohol, and a short chainester of long chain alcohol or acid; h) a polyglycerol ester, apolyethoxylated alcohol, and a quaternary amine; i) a polyglycerolester, a short chain ester of long chain alcohol or acid, and aquaternary amine; j) a polyglycerol ester, an amine oxide, and aquaternary amine; k) an alkyl or alkenyl alcohol, a short chain ester ofa long chain alcohol or acid, and a quaternary amine; l) an alkyl oralkenyl alcohol, a short chain ester of long chain alcohol or acid, andan amine oxide; m) a short chain ester of a long chain alcohol or acid,a polyethoxylated alkyl alcohol, and a quaternary amine; n) a shortchain ester of a long chain alcohol or acid, and a quaternary amine; o)an alkyl betaine and a polyethoxylated alcohol; p) an alkyl phospholipidand a polyethoxylated alcohol; q) a short chain ester of long chainalcohol or acid, an alkyl alcohol, and a dialkoxydimethicone; r) a shortchain ester of long chain alcohol or acid and a polyethoxylated alcohol;s) a short chain ester of long chain alcohol or acid and a quaternaryamine; t) a polyglycerol ester and a polyethoxylated alcohol; or u) analkyl carboxylate and a polyethoxylated alcohol.
 37. The method of claim33 wherein the composition further comprises dialkoxy dimethicone andpolyether/polysiloxane copolymer.
 38. The method of claim 33 wherein thecomposition further comprises at least one emollient.
 39. The method ofclaim 38 wherein the composition further comprises both both wax andliquid emollients in a weight ratio of 3:1 to 1:3 wax to liquidemollients.
 40. The method of claim 33 wherein the composition furthercomprises a salt.
 41. The method of claim 33 wherein the compositionfurther comprises a stabilizer.
 42. The method of claim 33 wherein thecomposition further comprises a fragrance.
 43. The method of claim 42wherein the fragrance is a perfume.
 44. The method of claim 33 whereinthe composition is in the form of a lotion, a gel, or a foam.
 45. Themethod of claim 33 wherein the composition is an aftershave.